The present invention relates in general to vehicle engines and in particular to an improved air intake manifold assembly for use in such a vehicle engine and method for producing the same.
An air intake manifold assembly of a multi-cylinder engine includes a plurality of branched air passageways or ducts. Each of the air passageways defines a generally tubular runner having an air intake port and an opposite air outlet port. The air intake port of the runner is connected to an associated plenum which supplies atmospheric, turbo, or supercharged air to the runner intake port, and the air outlet port is connected to a flange which is connected to an associated inlet port of each cylinder head of the engine to supply the air from the runner to each cylinder head. Conventional intake manifold assemblies are constructed of cast iron, magnesium, aluminum, and plastic.
A typical aluminum intake manifold assembly is produced entirely by conventional casting process. These manifolds typically include a plurality of tubes disposed having first ends connected with the outlet holes of an air intake plenum, and second opposite ends connected with the associated holes of a flange member which is adapted for mounting to a cylinder head of the engine.
A typical plastic multi-piece manifold assembly includes an upper half shell and a lower half shell which are joined together by a welding process. In some instances, the plastic multi-piece manifold assembly includes one or more inner shell pieces which are disposed within the upper and/or lower half shells. The inner shell can be lower partial inserts which are secured to lower half shell; upper partial inserts which are secured to the upper half shell, or both lower and upper partial inserts which are secured to the respective lower and upper half shells. The inserts are typically joined to the associated half shell by a conventional heat staking process or welding process. In some instances, a plurality of individual blow molded tubes is disposed within the upper and lower half shells and joined thereto by a conventional heat staking process. In both types of constructions, the inserts, or the inserts in cooperation with upper or lower half shells, define a corresponding number of runner paths through which air is supplied to the associated cylinder head of the engine.
One example of a two-piece intake manifold is disclosed in U.S. Pat. No. 4,440,120 to Butler. Butler discloses an upper shell section and a lower shell section with each section containing at least partial portions of the air runner ducts that lead to the individual engine intake valves. Both the upper and lower shell sections tend to be of the same material, typically a polymer or aluminum, but can be of different materials.
Another example of a multi-piece intake manifold is disclosed in U.S. Pat. No. 6,467,449 to Brassell et al. Brassell et al. disclose simplified upper and lower shell sections by transferring some of the runner complexity to an insert assembly mounted internal to the upper and lower shell sections. The insert assembly is most likely to be of a polymer material.